Ah well we had a good run before the first pedant stuck their oar in. I think you'll find that most who have passed their nav are aware that a true circumnavigation requires that one cross the equator and travel a path equal to or exceeding the earth's circumference. Those who also paid attention in met will understand that achieving this in a device propelled by atmospheric movement alone will attract an ever so slightly higher score for difficulty. Not taking anything away from those who sought to edumacate the rest of us gullible clots, but....